Effect of host density and host quality on oviposition strategy of Habrobracon Hebetor (Hymenoptera: Braconidae)

Host quality is an intrinsic feature that is determined by quantitative and qualitative differences in hosts. These differences can change nutritional resources available and consequently affect on life history traits of parasitoid. Competition plays an important role in the size، structure and stability of insect communities. The aim of this paper was the effect of host density and host quality on Habrobracon hebetor oviposition strategy. The experiments was performed on 5th instar larvae of Ephestia kuehniella in growth chamber at 25±1° C، 50-60% RH and a 16:8 (L: D) photoperiod. Results showed that access to more number of hosts (10 larvae) caused to increase the number of hosts parasitized and total number of eggs laid in the presented patch. Wasps that encountered with previously parasitized hosts by conspecific parasitized the less number of hosts and the total number of eggs laid was reduced than females that encountered only healthy larvae. In treatment that females were only introduced into paralyzed hosts the most number of eggs laid on parasitized host. Furthermore، patch quality did not effect on egg hatching rate and sex ratio. The results of this study could provide better conditions for mass rearing of H. hebetor. It is important to use the proper ratio of H. hebetor females and larvae host، because in trade off between the number of parasitized hosts and the average eggs laid، the maximum progeny with the best quality to be produced.